osfmk/kern/work_interval.c

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29
  30 #include <sys/work_interval.h>
  31
  32 #include <kern/work_interval.h>
  33
  34 #include <kern/thread.h>
  35 #include <kern/sched_prim.h>
  36 #include <kern/machine.h>
  37 #include <kern/thread_group.h>
  38 #include <kern/ipc_kobject.h>
  39 #include <kern/task.h>
  40 #include <kern/coalition.h>
  41 #include <kern/policy_internal.h>
  42
  43 #include <mach/kern_return.h>
  44 #include <mach/notify.h>
  45
  46 #include <stdatomic.h>
  47
  48 /*
  49  * Work Interval structs
  50  *
  51  * This struct represents a thread group and/or work interval context
  52  * in a mechanism that is represented with a kobject.
  53  *
  54  * Every thread that has joined a WI has a +1 ref, and the port
  55  * has a +1 ref as well.
  56  *
  57  * TODO: groups need to have a 'is for WI' flag
  58  *      and they need a flag to create that says 'for WI'
  59  *      This would allow CLPC to avoid allocating WI support
  60  *      data unless it is needed
  61  *
  62  * TODO: Enforce not having more than one non-group joinable work
  63  *      interval per thread group.
  64  *      CLPC only wants to see one WI-notify callout per group.
  65  */
  66
  67 struct work_interval {
  68         uint64_t wi_id;
  69         _Atomic uint32_t wi_ref_count;
  70         uint32_t wi_create_flags;
  71
  72         /* for debugging purposes only, does not hold a ref on port */
  73         ipc_port_t wi_port;
  74
  75         /*
  76          * holds uniqueid and version of creating process,
  77          * used to permission-gate notify
  78          * TODO: you'd think there would be a better way to do this
  79          */
  80         uint64_t wi_creator_uniqueid;
  81         uint32_t wi_creator_pid;
  82         int wi_creator_pidversion;
  83
  84 };
  85
  86 static inline void
  87 wi_retain(struct work_interval *work_interval)
  88 {
  89         uint32_t old_count;
  90         old_count = atomic_fetch_add_explicit(&work_interval->wi_ref_count,
  91             1, memory_order_relaxed);
  92         assert(old_count > 0);
  93 }
  94
  95 static inline void
  96 wi_release(struct work_interval *work_interval)
  97 {
  98         uint32_t old_count;
  99         old_count = atomic_fetch_sub_explicit(&work_interval->wi_ref_count,
 100             1, memory_order_relaxed);
 101         assert(old_count > 0);
 102
 103         if (old_count == 1) {
 104
 105                 kfree(work_interval, sizeof(struct work_interval));
 106         }
 107 }
 108
 109 /*
 110  * work_interval_port_convert
 111  *
 112  * Called with port locked, returns reference to work interval
 113  * if indeed the port is a work interval kobject port
 114  */
 115 static struct work_interval *
 116 work_interval_port_convert_locked(ipc_port_t port)
 117 {
 118         struct work_interval *work_interval = NULL;
 119
 120         if (!IP_VALID(port)) {
 121                 return NULL;
 122         }
 123
 124         if (!ip_active(port)) {
 125                 return NULL;
 126         }
 127
 128         if (IKOT_WORK_INTERVAL != ip_kotype(port)) {
 129                 return NULL;
 130         }
 131
 132         work_interval = (struct work_interval *) ip_get_kobject(port);
 133
 134         wi_retain(work_interval);
 135
 136         return work_interval;
 137 }
 138
 139 /*
 140  * port_name_to_work_interval
 141  *
 142  * Description: Obtain a reference to the work_interval associated with a given port.
 143  *
 144  * Parameters:  name    A Mach port name to translate.
 145  *
 146  * Returns:     NULL    The given Mach port did not reference a work_interval.
 147  *              !NULL   The work_interval that is associated with the Mach port.
 148  */
 149 static kern_return_t
 150 port_name_to_work_interval(mach_port_name_t     name,
 151     struct work_interval **work_interval)
 152 {
 153         if (!MACH_PORT_VALID(name)) {
 154                 return KERN_INVALID_NAME;
 155         }
 156
 157         ipc_port_t port = IPC_PORT_NULL;
 158         kern_return_t kr = KERN_SUCCESS;
 159
 160         kr = ipc_port_translate_send(current_space(), name, &port);
 161         if (kr != KERN_SUCCESS) {
 162                 return kr;
 163         }
 164         /* port is locked */
 165
 166         assert(IP_VALID(port));
 167
 168         struct work_interval *converted_work_interval;
 169
 170         converted_work_interval = work_interval_port_convert_locked(port);
 171
 172         /* the port is valid, but doesn't denote a work_interval */
 173         if (converted_work_interval == NULL) {
 174                 kr = KERN_INVALID_CAPABILITY;
 175         }
 176
 177         ip_unlock(port);
 178
 179         if (kr == KERN_SUCCESS) {
 180                 *work_interval = converted_work_interval;
 181         }
 182
 183         return kr;
 184 }
 185
 186
 187 /*
 188  * work_interval_port_notify
 189  *
 190  * Description: Handle a no-senders notification for a work interval port.
 191  *              Destroys the port and releases its reference on the work interval.
 192  *
 193  * Parameters:  msg     A Mach no-senders notification message.
 194  *
 195  * Note: This assumes that there is only one create-right-from-work-interval point,
 196  *       if the ability to extract another send right after creation is added,
 197  *       this will have to change to handle make-send counts correctly.
 198  */
 199 void
 200 work_interval_port_notify(mach_msg_header_t *msg)
 201 {
 202         mach_no_senders_notification_t *notification = (void *)msg;
 203         ipc_port_t port = notification->not_header.msgh_remote_port;
 204         struct work_interval *work_interval = NULL;
 205
 206         if (!IP_VALID(port)) {
 207                 panic("work_interval_port_notify(): invalid port");
 208         }
 209
 210         ip_lock(port);
 211
 212         if (!ip_active(port)) {
 213                 panic("work_interval_port_notify(): inactive port %p", port);
 214         }
 215
 216         if (ip_kotype(port) != IKOT_WORK_INTERVAL) {
 217                 panic("work_interval_port_notify(): not the right kobject: %p, %d\n",
 218                     port, ip_kotype(port));
 219         }
 220
 221         if (port->ip_mscount != notification->not_count) {
 222                 panic("work_interval_port_notify(): unexpected make-send count: %p, %d, %d",
 223                     port, port->ip_mscount, notification->not_count);
 224         }
 225
 226         if (port->ip_srights != 0) {
 227                 panic("work_interval_port_notify(): unexpected send right count: %p, %d",
 228                     port, port->ip_srights);
 229         }
 230
 231         work_interval = (struct work_interval *) ip_get_kobject(port);
 232
 233         if (work_interval == NULL) {
 234                 panic("work_interval_port_notify(): missing kobject: %p", port);
 235         }
 236
 237         ipc_kobject_set_atomically(port, IKO_NULL, IKOT_NONE);
 238
 239         work_interval->wi_port = MACH_PORT_NULL;
 240
 241         ip_unlock(port);
 242
 243         ipc_port_dealloc_kernel(port);
 244         wi_release(work_interval);
 245 }
 246
 247 /*
 248  * Change thread's bound work interval to the passed-in work interval
 249  * Consumes +1 ref on work_interval
 250  *
 251  * May also pass NULL to un-set work_interval on the thread
 252  *
 253  * Will deallocate any old work interval on the thread
 254  */
 255 static void
 256 thread_set_work_interval(thread_t thread,
 257     struct work_interval *work_interval)
 258 {
 259         assert(thread == current_thread());
 260
 261         struct work_interval *old_th_wi = thread->th_work_interval;
 262
 263         /* transfer +1 ref to thread */
 264         thread->th_work_interval = work_interval;
 265
 266
 267         if (old_th_wi != NULL) {
 268                 wi_release(old_th_wi);
 269         }
 270 }
 271
 272 void
 273 work_interval_thread_terminate(thread_t thread)
 274 {
 275         if (thread->th_work_interval != NULL) {
 276                 thread_set_work_interval(thread, NULL);
 277         }
 278 }
 279
 280
 281
 282 kern_return_t
 283 kern_work_interval_notify(thread_t thread, struct kern_work_interval_args* kwi_args)
 284 {
 285         assert(thread == current_thread());
 286         assert(kwi_args->work_interval_id != 0);
 287
 288         struct work_interval *work_interval = thread->th_work_interval;
 289
 290         if (work_interval == NULL ||
 291             work_interval->wi_id != kwi_args->work_interval_id) {
 292                 /* This thread must have adopted the work interval to be able to notify */
 293                 return KERN_INVALID_ARGUMENT;
 294         }
 295
 296         task_t notifying_task = current_task();
 297
 298         if (work_interval->wi_creator_uniqueid != get_task_uniqueid(notifying_task) ||
 299             work_interval->wi_creator_pidversion != get_task_version(notifying_task)) {
 300                 /* Only the creating task can do a notify */
 301                 return KERN_INVALID_ARGUMENT;
 302         }
 303
 304         spl_t s = splsched();
 305
 306
 307         uint64_t urgency_param1, urgency_param2;
 308         kwi_args->urgency = thread_get_urgency(thread, &urgency_param1, &urgency_param2);
 309
 310         splx(s);
 311
 312         /* called without interrupts disabled */
 313         machine_work_interval_notify(thread, kwi_args);
 314
 315         return KERN_SUCCESS;
 316 }
 317
 318 /* Start at 1, 0 is not a valid work interval ID */
 319 static _Atomic uint64_t unique_work_interval_id = 1;
 320
 321 kern_return_t
 322 kern_work_interval_create(thread_t thread,
 323     struct kern_work_interval_create_args *create_params)
 324 {
 325         assert(thread == current_thread());
 326
 327         if (thread->th_work_interval != NULL) {
 328                 /* already assigned a work interval */
 329                 return KERN_FAILURE;
 330         }
 331
 332         struct work_interval *work_interval = kalloc(sizeof(*work_interval));
 333
 334         if (work_interval == NULL) {
 335                 panic("failed to allocate work_interval");
 336         }
 337
 338         bzero(work_interval, sizeof(*work_interval));
 339
 340         uint64_t old_value = atomic_fetch_add_explicit(&unique_work_interval_id, 1,
 341             memory_order_relaxed);
 342
 343         uint64_t work_interval_id = old_value + 1;
 344
 345         uint32_t create_flags = create_params->wica_create_flags;
 346
 347         task_t creating_task = current_task();
 348         if ((create_flags & WORK_INTERVAL_TYPE_MASK) == WORK_INTERVAL_TYPE_CA_CLIENT) {
 349                 /*
 350                  * CA_CLIENT work intervals do not create new thread groups.
 351                  * There can only be one CA_CLIENT work interval (created by UIKit or AppKit)
 352                  * per each application task
 353                  */
 354                 if (create_flags & WORK_INTERVAL_FLAG_GROUP) {
 355                         return KERN_FAILURE;
 356                 }
 357                 if (!task_is_app(creating_task)) {
 358                         return KERN_NOT_SUPPORTED;
 359                 }
 360                 if (task_set_ca_client_wi(creating_task, true) == false) {
 361                         return KERN_FAILURE;
 362                 }
 363         }
 364
 365         *work_interval = (struct work_interval) {
 366                 .wi_id                  = work_interval_id,
 367                 .wi_ref_count           = 1,
 368                 .wi_create_flags        = create_flags,
 369                 .wi_creator_pid         = pid_from_task(creating_task),
 370                 .wi_creator_uniqueid    = get_task_uniqueid(creating_task),
 371                 .wi_creator_pidversion  = get_task_version(creating_task),
 372         };
 373
 374
 375         if (create_flags & WORK_INTERVAL_FLAG_JOINABLE) {
 376                 mach_port_name_t name = MACH_PORT_NULL;
 377
 378                 /* work_interval has a +1 ref, moves to the port */
 379                 work_interval->wi_port = ipc_kobject_alloc_port(
 380                         (ipc_kobject_t)work_interval, IKOT_WORK_INTERVAL,
 381                         IPC_KOBJECT_ALLOC_MAKE_SEND | IPC_KOBJECT_ALLOC_NSREQUEST);
 382
 383                 name = ipc_port_copyout_send(work_interval->wi_port, current_space());
 384
 385                 if (!MACH_PORT_VALID(name)) {
 386                         /*
 387                          * copyout failed (port is already deallocated)
 388                          * Because of the port-destroyed magic,
 389                          * the work interval is already deallocated too.
 390                          */
 391                         return KERN_RESOURCE_SHORTAGE;
 392                 }
 393
 394                 create_params->wica_port = name;
 395         } else {
 396                 /* work_interval has a +1 ref, moves to the thread */
 397                 thread_set_work_interval(thread, work_interval);
 398                 create_params->wica_port = MACH_PORT_NULL;
 399         }
 400
 401         create_params->wica_id = work_interval_id;
 402         return KERN_SUCCESS;
 403 }
 404
 405
 406 kern_return_t
 407 kern_work_interval_destroy(thread_t thread, uint64_t work_interval_id)
 408 {
 409         if (work_interval_id == 0) {
 410                 return KERN_INVALID_ARGUMENT;
 411         }
 412
 413         if (thread->th_work_interval == NULL ||
 414             thread->th_work_interval->wi_id != work_interval_id) {
 415                 /* work ID isn't valid or doesn't match joined work interval ID */
 416                 return KERN_INVALID_ARGUMENT;
 417         }
 418
 419         thread_set_work_interval(thread, NULL);
 420
 421         return KERN_SUCCESS;
 422 }
 423
 424 kern_return_t
 425 kern_work_interval_join(thread_t            thread,
 426     mach_port_name_t    port_name)
 427 {
 428         struct work_interval *work_interval = NULL;
 429         kern_return_t kr;
 430
 431         if (port_name == MACH_PORT_NULL) {
 432                 /* 'Un-join' the current work interval */
 433                 thread_set_work_interval(thread, NULL);
 434                 return KERN_SUCCESS;
 435         }
 436
 437         kr = port_name_to_work_interval(port_name, &work_interval);
 438         if (kr != KERN_SUCCESS) {
 439                 return kr;
 440         }
 441         /* work_interval has a +1 ref */
 442
 443         assert(work_interval != NULL);
 444
 445         thread_set_work_interval(thread, work_interval);
 446
 447         /* ref was consumed by passing it to the thread */
 448
 449         return KERN_SUCCESS;
 450 }